/*
 * Copyright (c) 2016, 2017, 2018, 2019 FabricMC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package net.fabricmc.indigo.renderer.mesh;

import java.util.function.Consumer;

import net.fabricmc.fabric.api.renderer.v1.mesh.Mesh;
import net.fabricmc.fabric.api.renderer.v1.mesh.QuadView;


/**
 * Implementation of {@link Mesh}.
 * The way we encode meshes makes it very simple.
 */
public class MeshImpl implements Mesh {
    /** Used to satisfy external calls to {@link #forEach(Consumer)}. */
    ThreadLocal<QuadViewImpl> POOL = ThreadLocal.withInitial(QuadViewImpl::new);
    
    final int[] data;

    MeshImpl(int data[]) {
        this.data = data;
    }
    
    public int[] data() {
        return data;
    }
    
    @Override
    public void forEach(Consumer<QuadView> consumer) {
        forEach(consumer, POOL.get());
    }

    /**
     * The renderer will call this with it's own cursor
     * to avoid the performance hit of a thread-local lookup.
     * Also means renderer can hold final references to quad buffers.
     */
    void forEach(Consumer<QuadView> consumer, QuadViewImpl cursor) {
        final int limit = data.length;
        int index = 0;
        while(index < limit) {
            cursor.load(data, index);
            consumer.accept(cursor);
            index += cursor.stride();
        }
    }
}
